The use of parking brakes is well-known in the prior art. Parking brakes are especially used in construction and work machines, for example, wheel loaders, shovel dozers or dumpers. Parking brakes are usually arranged as friction brakes that are attached to the transmission or arranged in the powertrain, being designed as air cooled brakes, for example drum or plate brakes, as well as oil cooled brakes, for example rotary disk brakes in an oil bath.
Prior art solutions including air cooled parking brakes have the disadvantage of contamination causing an increase wear and tear. In oil cooled parking brakes the available braking power is restricted because of its reduced volume; furthermore, in addition high drag torque is also disadvantageously generated. Prior art parking brakes can only conditionally be used as auxiliary brakes for main brakes because the input power is limited during continuous braking; the total thermal energy is not dissipated via an active cooling system but via thermal radiation.
From DE 103 39 245 A1, a brake control system for a vehicle comprising a parking brake is known, where the main brakes of the vehicle are operated instead of, or in addition to, the parking brake when the parking brake is controlled by the driver, and the speed of the vehicle exceeds a specified speed range, in order to protect the parking brake. Furthermore, the parking brake is only disengaged once the main brake is operating within a specified range. This ensures that the main brakes are primed and full braking power is available to the driver.